1. Field of the Invention
This invention relates to a slide fastener suitable for use in attaching a cover sheet to a seat of a car, etc. and connecting a huge sheet with another, and more particularly to a slide fastener which can keep in a closed state after a slider is removed from a pair of coupling element rows, with the slide fastener closed, in attaching a cover sheet or joining sheets or the like.
2. Description of the Related Art
Conventionally, in slide fasteners to be used in attaching a seat cover and connecting artificial turfs, carpets, etc., sliders are left each on opposed coupling element rows after the individual slide fasteners are closed. Since the seams of the sheets bulge locally due to the sliders remaining, the resulting sheet would have an unsightly appearance, and particularly in the case of artificial turfs, carpets or the like, the individual slide fastener tends to split as the corresponding slider is broken when stamped, and otherwise the sliders might hurt an athlete's body when he or she falls on the turf. In order to avoid these inconveniences, for example, Japanese Patent Laid-Open Publication No. HEI 6-14806 discloses a concept of removing the slider from the fastener chain after the sheets are join by closing the slide fastener and attaching a top stop assembly to the opposed fastener tapes contiguously to top ends of the opposed coupling element rows to retain the coupled state of the coupling elements after the slider is removed.
In joining sheet-like articles, such as seat covers, artificial turfs and carpets, by closing the opposed fastener stringers sewn to connecting edges, since pulling forces perpendicular to the coupling element rows act on the fastener chain in opposite directions, the coupling element rows tend to split. Consequently, the fastener chain is extended in such a manner that the terminal portions of the coupling element rows project beyond the end of connecting edge of the sheet in an effort that the pulling forces do not act at the terminal portions of the coupling element rows. After the sheets are joined together, the projected part of the fastener chain is folded inwardly of the sheets so that the appearance of the sheets are not impaired and so that the closed fastener chain is prevented from being split.
In the slide fastener disclosed in Japanese Patent Laid-Open Publication No. HEI 6-14806, the attachment base portions of male and female members of the top stop assembly attached to the terminal portions of the coupling element rows extends beyond the end of the connecting edges of the sheets, or cutaways are formed in the fastener tapes about the top stop assembly, so that the male and female members of the top stop assembly are retained in an interlocked state in such a manner that the opposite pulling forces acting on the fastener stringers does not influence on the interlocking force of the top stop assembly members, thereby preventing the coupling element rows from splitting. As is apparent from the foregoing description, in this conventional type of slide fasteners, in order to prevent the coupling element rows from being split due to the opposite pulling forces acting on the fastener chain, the slide fastener is set longer than the length of the actual seem of the sheets so that the terminal portions of the coupling element rows extend beyond the end of the connecting edges of the sheets. With this arrangement, partly because the cost of production is increased and partly because the end portion of the fastener chain projects from the end of the connecting edges of the sheets, it is necessary to fold the end portion of the fastener chain under the sheets.
Particularly in the slide fastener disclosed in Japanese Patent Laid-Open Publication No. HEI 6-14806, in order to prevent the coupling element rows from being split due to the opposite pulling forces acting on the fastener chain, it is necessary to cut the top-stop-attaching tape portions of the slide fastener in chevron so that the number of manufacturing steps is increased to lower the productivity.
Further, the uneven surface of ground in the case of turfs and carpets and the curved surfaces of a seat in the case of seat cover cause the fastener chain to bend to give thrusting forces on the coupling elements in the direction of thickness of the fastener tape so that the coupling element rows tend to split. The conventional top stop assembly members has however only inadequate interlocking force against the thrusting force acting on the coupling elements in the direction of thickness of the fastener tape.